Wood-preserving composition and fungicide



Patented July 16, 1929.

UNITED. STATES I 1,720,905 PATENT OFFICE.

ALBERT Ii. KLEES AND ROLAND P. SOULE, OF NEW YORK, N. Y., ASSIGNORS TO COM- ".BUSTION UTILITIES CORPORATION, OE NEW YORK, N. Y., A CORPORATION OF MAINE.

No Drawing.

This invention relates to wood preservatives and more particularly to a new and useful article of manufacture particularly I suitable for use for a wood preserving composition and fungicide.

The decay of wood is generally believed to be due almost entirely to fungi, marine borers, or other organisms which live on the cellulose and lignin composing the Wood 1 cells. In order to: prevent decay and prolong the life of structural timbers and railroad ties, piling, and other wood products of all kinds, many types of so-called-wood preservatives have been developed which are generally in liquid form and are forced into the fibers of the wood, usually under pressure. Almost all the wood preservatives in use commercially at the present time are made from coal tar creosote, refined water gas tar, creosote coal tar solutions, Water gas tar distillate and-watengas tar solution, together with zinc chloride. The chief quality requisite for a good wood preservative is that of an antiseptic capable of killing hostile organisms, and the toxic properties of the wood preservatives mentioned above are be lieved, to be chiefly due to their content of low boiling aromatic hydrocarbons.

It was. formerly believed that the effectiveness of oils, in particular of petroleum oils, which are non-toxic, as wood preserving agents is due in large part to their waterproofing action, i. e. that the oil fills the woodcells and prevents subsequent entry of water. Modern theory, however, holds that the amount of water-proofing thus obtained is negligible, and that-the principal value of such non-toxic oils when applied to material subject toshock or mechanical wear,

40 such as railroad ties, is due to another cause ;--that is to their fiber binding properties, which tend not only to gind the wood fibers together but also by preserving their elasticitygreatly to extend the life of the timbers treated therewith. For this reason there is being introduced the practice of adding asphaltic petroleum fuel oil, which has excellent fiber binding properties, as a diluent to the toxic and rather expensive tar products in order to secure cheap products combining the toxic and fiber binding prloperties demanded of a good preserving 01 The wood preserving oils in general use at present are quite expensive, and when an WOOD-PRESERVING COMPOSITION AND FUNGICIDE.

Application filed January 23, 1924. Serial No. 688,093.

attempt is made. to reduce their cost by blending them with asphaltic petroleum oils their toxicity islowered far below what would be expected from the mere diluent effect of the addition of the petroleum oil. Moreover these oils are apt to lose their toxic value on long usage because of loss of volatile aromatic hydrocarbons and low boillng phenols! and cresols by evaporation. Other undesirable features of the present commercial wood preserving oils which the trade is trying to overcome are their rather high viscosity, which results in decreased penetration into and absorption by the wood; and the precipitation of sludge in blends with petroleum oil, resulting in deposits on the heating coils of the treating cylinders and slime on the timber, making it awkward to handle.

Thev primary object of the present invention is to provide a wood preserving composition and fungicide which is relatively inexpensive and at the same time possesses a high fungicidal toxicity and superior fiber binding properties.

A further object of the invention is'to provide a woodpreserving composition and fungicide which possesses a low degree of' water solubility and a low volatility without sacrifice of penetration or absorption properties.

Another object of the present invention is to provide a wood preserving composition and fungicide which Willblend readily with petroleum oils without substantialsludge precipitation.

With these and other objects in view the invention consists in the new wood preserving composition and fungicide hereinafter described and particularly defined in the claims.

The wood preserving composition and fungicide which comprises the subject matter of the present invention'consists essentially in a mixture of certain of the primary or only partially decomposed primary liquid distfllates of coal or other bituminous material. In the British patent of Henry 0. Loebell #216,488 of May 23, 1923, and in- U. S. Patent #1,426,159, ranted August 15, 1922, to Henry L. Do erty, two processes are described by either of which fuel may be carbonized and gasified with the production of combustible gas, coke and liquid tar of such a primary nature.

In accordance with processes such as these, the bituminous or carbonaceous material such as ordinary coal, oil shale, or lignite, is fractionally distilled under conditions such that the liquid products of distillation condensed from the mixture of volatile products driven off from the coal are entirely different in their roperties from coke oven tar, the origin 0 ordinary coal tar wood preservatives. The method used in the above processes for effecting a fractional distillation of the fuel consists essentially in passing a ,body of the fuel in a column through a shaft furnace and subjecting it during-its passage through the upper part of the column to a fractional distillation by direct heat contact with a current of hot. gases, said gas current being the sole heat-carrying medium by means of which the heat for efiecting the carbonizing of the fuel is supplied. This hot gas current is introduced into the lower portion of the upper section of the fuel column and as the gases pass upwardly they give up their sensible heat to the fuel so that as it advances downwardly it is gradually heated to higher and higher temperatures by contact with hotter and hotter gases, and the fractional distillation and removal of the volatile constituents of higher and higher boiling points thus takes place. At the same time the current of heating gas is gradually cooled as it rises toward the top of the column and the volatile products of the distillation are picked up by these gases and carried along therewith, being cooled by contact with fresh portions of fuel so that they are rarely subjected to temperatures much above those at which they are first liberated from the coal. The tar oils condensed from the above gases comprises essentially a mixture of primary or of primary and only partially cracked non-aromatic hydrocarbon oils, together with a high percentage of primary tar acids and with a small percentage of nitrogen bases.

The wood preserving composition and fungicide which forms the subject matter of the present invention may be readily prepared by a refining treatment such as by dehydration, filtration or distillation from tar oils similar in nature to those obtained in the aforementioned processes or from fractions of such tars. The resultant composition may be described as consisting essentially of two parts, the first comprising a mixture of high boiling compounds soluble .in alkali, and similar in a general way to the higher homologues of phenol which occur in very small quantity in ordinary coke oven tar, but differing from them by having a lower density for the same boiling point; the second part consisting almost entirely of a mixture of nonaromatic tar oils composed principally of hydrocarbons which are both saturated (parafiinic and naphthenic), and unsaturated (for the most part cyclic or hydro-aromatic), but containing only small amounts of aromatic hydrocarbons '(benzene, naphthalene, anthracene and their homologues).

The improved wood preservative may be further described as a mixture containing at least fifteen per cent of alkali-soluble compounds, hereinafter designated as primary tar acids, and the remainder composed chiefly of non-aromatic tar oils; that at least yfifty percent of the. primary tar acids distill above 220 centigrade; and that at least \ten percent of the non-aromatic tar oils remain after a single treatment with concentrated sulphuric acid. It is obvious that the actual chemical composition of any particular distillate of tar which is produced under special conditions such as those de scribed above, will vary between wide limits, depending on the type of coal from which it is derived, on the method used for carbonizing such coal and also to a large extent onthe amount of steam used in the process. A Middle Western bituminous coal .of about thirty percent volatile content when distilled between temperatures ranging from about 200 centigrade to about 900 centigrade in a machine similar to those used in carrying out the above processes has for example been found to yield under ordinary conditions a tar oil of about 1.02 specific gravity, which on distillation to about 350 centigradeyields-a distillate comprising approximately twenty-eight per cent tar acids, two percent nitrogen bases, four percent paraffinic hydrocarbons, nine percent naphthenic hydrocarbons and approximately fifty-seven percent unsaturated hydrocarbons. No more than a trace of aromatic hydrocarbons was found to be present in this oil. As the temperature of carbonization increases it may be noted as a general rule that the specific gravity of the resultant tar oil rises, the percentage of sulphonation residue is decreased andusually the tar acid content also decreases.

A corresponding distillate of a hightemperature coke-oven or gas-works tar recovered from a similar coal has a tar acid content of less than five percent by weight, which is made up principally of phenol and the cresols in the ratio of about one to two, together with about twenty percent of the higher homologues. The tar acids of a distillate from a primary or only partially decomposed primary tar such' as that under consideration contain, on the other hand, only a very small proportion'of henol and cresols; in general more than fi ty percent of the tar acids present being found to have the same boiling points as the xylenols and' higher homologues.

The decreasein the specific gravity of any homologous series of tar acids as the boilmg point increases indicates the presence of side chains of lower density attached to the cyclic nucleus. In the higher homologues present in ordinary high temperature tar a sharp rise in density and a notable increase in the viscosity of the fractions mark the appearanceof alphaand beta-naphthols; likewise in primary and-only partially decomposed tar oils a similar rise in density and increase in viscosity would appear to indicate the presence of bi-cyclic compounds of a similar nature. However, these higher homologues which are present in this composition have been investigated and have been found to contain neither alpha nor beta-naphthol; but among other compounds they contain naphthol derivatives having alkyl side chains or hydrogen or both alkyl side chains and hydrogen attached to the naphthol nucleus.

Likewise it has been found that the unsaturated hydrocarbons which comprise one of the two largest component groups of these primary tar distillates are largely ,cyclic in structure, and are hydrogenated and alkylated derivatives of the aromatic hydrocarbons. Among the hydrogenated unsaturated hydrocarbons present in these tar oils dihydro-mxylene and dihydroanesitylene have been identified. Man of the higher boiling members of the series have been found to possess from three to five double bonds and are apparently polycyclic.

The present wood preserving composition and fungicide may be considered as a primary or only partially decomposed primary liquid distillate of coal or other bituminous material. The term primary is-applied as a generic term of liquid components of coal having substantially the same chemical composition and characteristics which they possess at the instant that they arefirst liberated in the volatile state from the coal by heat, to distinguish them from the so-called high temperature or coke-oven tar, which possesses an entirely different chemical composition and properties and is a decomposition product resulting from the cracking down of the primary components liberated from the coal.

while in the volatile state at the high temperatures to which they are exposed in the coke oven. By carbonizing coal under conditions which prevent decomposition of this primary distillate to low boiling phenols and aromatic hydrocarbons, for example, according to a method such as that described in the aforementioned patent of Loebell, such a primary or partially decomposed primary tar may be obtained, and its composition may beeasily regulated so as to combine high boiling tar acids with saturated and unsaturated hydro carbons in that ratio which is most desireable for any particular wood preserving composition. Likewise the tar oil obtained is effected by passing a circulation of hot water gas in heat-transferring relation therewith, would produce a similar primary or partially decomposed primary tar.

As previously indicated the chief function of a preserving oil is twofold: (1) It must prevent decay by killing wood destroying organisms, or by inhibiting their growth; (2) in case of timber subjected to shock it should prolong the life of the treated wood.

The coal distillation product from which the composition forming the subject matter of the present invention may be prepared is essentially a primary tarwhich has not been decomposed to the extent represented by the composition known as ordinary creosote oil.

This primary tar oil or its distillates or mixturesof these two with each other and/or with petroleum products all constitute effective wood preservatives. Likewise mixtures of this tar oil or its distillates or of blends of the tar oil and distillate with coke oven or water gas tar, or with blends of coke oven or water gas tar with their respective distillatcs, are all eflectivewood preservatives. In the first place these tar oil mixtures containing primary tar acids are highly p0is0nous to fungi. It has been found that the concentration of coke oven creosote necessary to inhibit the growth of fomes annosus (a common wood destroying organism) is more than one hundred times the concentration of the so-called creosote fraction (that is, the fraction of primary tar distillate boiling over the same range as that of the creosote cominonly used as a wood preservative) of this primary tar oil needed to effect the same result. In addition it has (for the same vis- The viscosity of the original tar oil is so low that at the Wood-treating temperature of 180 Fahrenheit it can be used undistilled and still give satisfactory penetration and absorption. The highboiling and highly toxic tar acids which are present inthis oil are not lost so readily by evaporation as the volatile aromatic hydrocarbons to which most of the toxicity of coke oven tar is believed'to be due. acids are far less corrosive than the low boiling and chemically active phenols and cresols presentin ordinary creosote. The oils form'- ing the present invention carry little, if any, carbolic or cresylic acids, but they do contain high percentages of organic alkali-soluble compounds resembling the phenols, but of a boiling point much higher than that of cresylic acid. As previously stated these high boiling primary'tar acids have a much These high boiling tar other purposes.

'lower density for the same boiling point than the higher true phenolic homologues which occur in small quantity in ordinary coke oven tar ;in fact they are believed to be largely hydrogenated and alkylated derivatives having more hydrogen attached to the nucleus or having more side chains, and being therefore of a much higher molecular weight than the carbolic and cresylic acids. Since the water solubility of tar acids decreases rapidly with rising molecular weights it would be expected, and leaching tests have shown, that these primary tar acids are far less soluble than ordinary phenols.

Finally the present wood preserving composition is very well adapted for extending the mechanical life of treated timber, since the tar oil itself is sufiiciently nonviscous to be used satisfactorily after simple dehydration, and there is therefore made available a relatively cheap, very toxic non-volatile oil with a large content. of high boiling hydrocarbons, possessing good fiber-binding properties. These hydrocarbon oils consist largely of cyclic unsaturated and naphthenic hydrocarbons which are closely related chemically to asphaltic petroleum compounds. This constitutional similarity is of marked advantage when it is desired to blend the present tar-oils or their distillates or the tar oil-distillate mixture with petroleum fuel oils. Much less sludge is precipitated than with the corresponding coke oven products, and a superior commercial blend is obtained. But one of the greatest advantages in using the present tar oils or their distillates is in the fact that, contra to the coke-oven creosote oils, they may be diluted to a far greater extent by blending with petroleum products or aromatic hydroparbon oils before their effective toxicity is The mixture of high boiling primary tar acids and non-aromatic tar oils comprising the above composition is known to be valuable not only as a wood-preservative and fungicide, but also when used alone or in admixture with other bodies, as disinfectants and germicides, flotation oils, and for many It is not necessary that the present wood preserving composition be produced from tars obtained in the Doherty and Loebell processes described above.

The term tar acid has been used throughout the foregoing description as a (generic term to define alkali soluble hydroxyl erivatives of the cyclic hydrocarbons which are obtainablgjrom'coal and similar bituminous materials and distillates and in which the OH group is attached directly to the cyclic nucleus. Similarly the term nitrogen bases has been used in the above description as a generic term to define the nitrogen derivatives of cyclic hydrocarbons,

all of which have a nitrogen grou replacingone of the CH groups of the eye '0 nucleus,

asexemplified by the pyridine-quinolinemary or only partially decomposed primary.

tar. It is to be understood, therefore, that the term primary tar acids is used in the specification and claims as a generic term to define alkali-soluble hydroxy compounds closely related to the phenols and com rising hydrogenated or alkylated or oth hydrogenated and alkylated derivatives of phenol, naphthol and cyclic and polycyclic phenolic homologs.

The preferred form of the invention having been thus described, what is claimed as new is:

1. As an article of manufacture, a refined, dehydrated product comprising primary tar acids, of which at least fifty percent distil above 220 centigrade.

2. As an article of manufacture a refined, dehydrated product comprising high-boiling primary tar acids and non-aromatic hydrocarbons.

3. As an article of manufacture a refined, dehydrated product comprising high-boiling primary tar acids in admixture with unsaturated non-aromatic hydrocarbons.

4. As an article of manufacture a refined, dehydrated product comprising high-boiling primary tar acids and saturated non-aromatic hydrocarbons.

5. As an article of manufacture a product containing high-boiling primary tar acids in admixture with a heavy oil of petroleum origin.

6. As an article of manufacture a refined, dehydrated product containing high-boiling primary tar acids and non-aromatic hydrocarbons in the ratio of about one to two by Weight.

7. As an article of manufacture a product consisting of more than twenty percent primary tar acids, of which at least fifty percent distil above 220 centigrade, and more than fifty percent unsaturated non-aromatic hydrocarbons, together with a balance consisting chiefly of saturated hydrocarbons.

8. A wood-preserving composition and fungicide comprising a blend of a primary or only partially decomposed primary tar-oil in admixture with a high-boiling fraction of said tar-oil.

9. A wood-preserving composition and fungicide comprising a primary or only partially decomposed liquid distillate of coal or other bituminous material in admixture with a heavy oil of petroleum origin.

10. A wood-preserving composition and fungicide comprising a primary or only partially decomposed liquid distillate of coal or other bituminous material in admixture with a fraction of said distillate and a heavy oil of petroleum origin.

11. A refined, dehydrated wood-preserving composition and fungicide comprising primary tar acids fifty percent of which boil above 220 centigrade, and at least forty percent non-aromatic hydrocarbons.

12. A refined, dehydrated wood-preserving composition and fungicide comprising at least twenty per cent primary tar acids, fifty percent of which boil above 220 centigrade, and at least forty percent non-aromatic hydrocarbons.

13. A Wood-preserving composition comprising a mixture of primary tar acids of which at least fifty percent distil above 220 centrigrade and non-aromatie hydrocarbons, together with heavy oils of petroleum origin.

14:. A refined, dehydrated wood-preserving composition and fungicide comprising at least twenty per cent high-boiling primary tar acids together with a balance composed chiefly of non-aromatic hydrocarbons, at least ten percent of which remain after a single treatment with concgntrated sulphuric acid. a

15. A wood-preserving composition and fungicide comprising a primary or only partially decomposed primary tar-oil in admixture with the distillate of a coke-oven or water gas tar.

16. A wood-preserving composition and fungicide comprising a primary or only partially decomposed primary tar-oil in admixture with the blend of a coke-oven or water gas tar with its respective distillate.

17. A wood-preserving composition and fungicide comprising a distillate of primary or only partially decomposed primary taroil in admixture with the distillate of cokeoven or water gas tar.

18. A wood-preserving composition and fungicide comprising a distillate of primary or only partially decomposed primary tar-oil in admixture with the blend of a coke-oven or water gas tar with its respective distillate. In testimony whereof I affix my signature.

ROLAND P. SOULE. 

